Still had 1 address policies cached at shutdown

On moria1, each time I do a controlled shutdown, I see:

Apr 12 11:17:49.154 [warn] Still had 1 address policies cached at shutdown.     
Apr 12 11:17:49.154 [warn]   1 [13]: reject *4:*                                

This is on git master (0.3.1.0-alpha-dev), but it's been happening for some months.

See also legacy/trac#672 (moved) and legacy/trac#16539 (moved) for the previous instances of this bug.